1. Field of the Invention
The present invention relates to an ink-jet printer, or an ink-jet printer as an outputting apparatus such as a facsimile, an image processing apparatus, or an image recording apparatus, and a maintenance method for the ink-jet printer.
2. Description of the Related Art
In an ink-jet printer, in which an ink is supplied to a recording head from an ink supply source such as an ink tank, and a recording is carried out by jetting the ink from the recording head, when the ink stays for a long time in an ink supply system from the ink supply source up to the recording head, a moisture of the ink inside an ink supply path is evaporated. Moreover, due to entering of air into the ink supply path, an air bubble is developed. Therefore, the ink inside the ink supply system is thickened. Consequently, it is preferable that all the ink inside the ink supply system is replaced at fixed intervals, and there is not thickened ink or air bubble etc. inside the ink supply system.
An ink-jet printer including a purge unit which discharges, at every fixed interval, a certain amount of ink from the recording head for maintaining an optimum viscosity of the ink inside the ink supply system has hitherto been known.
However, in an ink-jet printer which discharges a certain amount of ink at every fixed interval, during the fixed interval, a certain amount of ink is discharged irrespective of an amount of ink consumed for printing, and an amount of ink consumed for a recovery operation of a recording head. Therefore, ink which is not required to be replaced, in other words, an amount of ink consumed by printing, a preparatory jetting (flushing) along with the printing, or the like, is discharged wastefully. Moreover, when the ink is supplied to the recording head via a flexible tube etc., since the ink inside the tube is also required to be replaced, the amount of ink to be discharged becomes large.
Therefore, in an ink-jet printer described in Japanese Patent Application Laid-open No. 10-337881, for example, an amount of ink to be discharged at the time of a purge process is let to be an amount corresponding to the number of dots remained after subtracting the number of dots used practically in recording, from a predetermined number of dots which is set in advance for each type of ink, and a wasteful consumption of the ink is prevented.
However, in the ink-jet printer described in Japanese Patent Application Laid-open No. 10-337881, for calculating an amount of ink to be discharged, it is necessary to memorize the number of dots used at the time of actual recording, and a large memory capacity is required.